The present invention relates to a head restraint for a vehicle seat, in particular for a motor vehicle seat, having a first subassembly for resting against the head of the occupant, and a vertically adjustable, second subassembly, with the first subassembly moving forward relative to the second subassembly in the event of a crash.
A head restraint of this type is disclosed in DE 39 00 495 A1. In the event of a crash, the distance between the head of the occupant and the head restraint is reduced in order to avoid whiplash (cervical vertebrae syndrome).
One aspect of the present invention is the provision of an improved head restraint. In accordance with one aspect of the present invention, a head restraint for a vehicle seat, in particular for a motor vehicle seat, includes a first subassembly for resting against the head of the occupant, and a vertically adjustable, second subassembly, with the first subassembly moving forward relative to the second subassembly in the event of a crash. Further in accordance with this aspect, a third subassembly of the head restraint is arranged below the second subassembly, and the first subassembly moves upward relative to the third subassembly in the event of a crash.
By virtue of a third subassembly of the head restraint, which subassembly is arranged below the second subassembly, being provided relative to which the first subassembly moves upward in the event of a crash, an initial erroneous positioning of the head restraint level with the neck can be corrected, so that the padding of the head restraint comes as close as possible to the back of the occupant""s head. This protects the occupant even better from injury, in particular from xe2x80x9ccervical vertebrae syndromexe2x80x9d and from breaking the neck. The extent of the movement upward depends on the height set for the head restraint.
The present invention, with which the crash characteristics of the head restraint are improved, can be used in all types of vehicle seats, for example in front seats or rear seat benches of motor vehicles, or in aircraft seats. The head restraint is preferably designed for a rear-end crash, but may also be correspondingly designed for the event of a head-on crash. The head restraint may be part of an automatic head restraint adaptation system, i.e. the height of the head restraint is set automatically via the longitudinal setting of the vehicle seat. In the rearmost position of the vehicle seat, the head restraint takes up its highest position, and in the front-most position its lowest position. The height of the head restraint can optionally be readjusted by a manual height-setting means.
For drives (e.g. driving mechanisms for respectively moving the first subassembly forward relative to the second subassembly and upward relative to the third subassembly in the event of a crash) which are to be constructed in as simple a manner as possible, it is preferable for the first subassembly to be moveable relative to the second subassembly (forwards) and for the second subassembly to be moveable relative to the third subassembly (upwards). The movements may be purely translatory, combinations of a translatory and a pivoting movement, or combinations of two pivoting movements. In the latter case, translatory movement can be produced again, for example by means of sliding guides. Lever arms, with which relatively large paths can Then be covered, are advantageous for pivoting movements of this type. The different movements can be controlled better by using separate energy stores, trains of mechanisms and guides, and by using common release mechanisms. For impacts against the head restraint taking place outside the event of a crash, a safety catch is preferably provided for preventing unintended activation of the crash-active head restraint.
Within the context of a modular construction and for better interchangeability and for short actuating distances and a great saving on structural space, it is advantageous if all of the subassemblies, including crash-sensitive sensors, energy stores, trains of mechanisms and other driving elements, are integrated within the head restraint, i.e. form a closed unit in the initial state.
Internal supports enable the extended head restraint to be secured before being retracted as a consequence of the occupant""s head striking against it, and translatory extension movements of the head restraint provide more possibilities in this case. The securing of the released state by a special catch of this type has the advantage that the occupant""s head cannot transmit any energy reversibly into the head restraint, which might cause his head to be re-accelerated.
As a catch of this type, a freewheel is preferably provided which blocks a pivoting device moving at the same time, with the result that the latter is used as a support. A freewheel of this type may also be provided in the case of a vehicle seat, in whose backrest an upper part of the backrest, which part is provided with a head restraint, pivots forward, in the event of a crash, from an initial state, relative to a lower part of the backrest, the freewheel then blocking a pivoting movement of the upper part to the rear. If arranged in the head restraint, the freewheel may be effective, for example, between the pivoting device and a head restraint rod and may be released again preferably at a certain height on the head restraint rod, for example in a section of smaller diameter.